Is it possible to use 1 mudfish account on 2 pc at the same time?
Unfortunately it's not possible. Each machine should have a separated Mudfish account. Please check Manage aliases section about how to create a sub (alias) account which shares your mudfish credits.
How can I delete or deactivate my account?
This is unrecoverable action so please be careful if you really like to perform.
Please sign in at http://accounts.en.loxch.com/ link. At there you can find "Close account" menu to delete your account.